[PATCH v9 15/17] KVM: arm64: implement ITS command queue command handlers
Marc Zyngier
marc.zyngier at arm.com
Thu Jul 14 03:38:08 PDT 2016
On 13/07/16 02:59, Andre Przywara wrote:
> The connection between a device, an event ID, the LPI number and the
> associated CPU is stored in in-memory tables in a GICv3, but their
> format is not specified by the spec. Instead software uses a command
> queue in a ring buffer to let an ITS implementation use its own
> format.
> Implement handlers for the various ITS commands and let them store
> the requested relation into our own data structures. Those data
> structures are protected by the its_lock mutex.
> Our internal ring buffer read and write pointers are protected by the
> its_cmd mutex, so that only one VCPU per ITS can handle commands at
> any given time.
> Error handling is very basic at the moment, as we don't have a good
> way of communicating errors to the guest (usually an SError).
> The INT command handler is missing from this patch, as we gain the
> capability of actually injecting MSIs into the guest only later on.
>
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
> ---
> virt/kvm/arm/vgic/vgic-its.c | 599 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 598 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 60108f8..28abfcd 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -33,6 +33,67 @@
> #include "vgic.h"
> #include "vgic-mmio.h"
>
> +/*
> + * Creates a new (reference to a) struct vgic_irq for a given LPI.
> + * If this LPI is already mapped on another ITS, we increase its refcount
> + * and return a pointer to the existing structure.
> + * If this is a "new" LPI, we allocate and initialize a new struct vgic_irq.
> + * This function returns a pointer to the _unlocked_ structure.
> + */
> +static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid)
> +{
> + struct vgic_dist *dist = &kvm->arch.vgic;
> + struct vgic_irq *irq = vgic_get_irq(kvm, NULL, intid), *oldirq;
> +
> + /* In this case there is no put, since we keep the reference. */
> + if (irq)
> + return irq;
> +
> + irq = kzalloc(sizeof(struct vgic_irq), GFP_KERNEL);
> + if (!irq)
> + return NULL;
> +
> + INIT_LIST_HEAD(&irq->lpi_list);
> + INIT_LIST_HEAD(&irq->ap_list);
> + spin_lock_init(&irq->irq_lock);
> +
> + irq->config = VGIC_CONFIG_EDGE;
> + kref_init(&irq->refcount);
> + irq->intid = intid;
> +
> + spin_lock(&dist->lpi_list_lock);
> +
> + /*
> + * There could be a race with another vgic_add_lpi(), so we need to
> + * check that we don't add a second list entry with the same LPI.
> + */
> + list_for_each_entry(oldirq, &dist->lpi_list_head, lpi_list) {
> + if (oldirq->intid != intid)
> + continue;
> +
> + /* Someone was faster with adding this LPI, lets use that. */
> + kfree(irq);
> + irq = oldirq;
> +
> + /*
> + * This increases the refcount, the caller is expected to
> + * call vgic_put_irq() on the returned pointer once it's
> + * finished with the IRQ.
> + */
> + kref_get(&irq->refcount);
> +
> + goto out_unlock;
> + }
> +
> + list_add_tail(&irq->lpi_list, &dist->lpi_list_head);
> + dist->lpi_list_count++;
> +
> +out_unlock:
> + spin_unlock(&dist->lpi_list_lock);
> +
> + return irq;
> +}
> +
> struct its_device {
> struct list_head dev_list;
>
> @@ -62,12 +123,70 @@ struct its_itte {
> u32 event_id;
> };
>
> +/*
> + * Find and returns a device in the device table for an ITS.
> + * Must be called with the its_lock mutex held.
> + */
> +static struct its_device *find_its_device(struct vgic_its *its, u32 device_id)
> +{
> + struct its_device *device;
> +
> + list_for_each_entry(device, &its->device_list, dev_list)
> + if (device_id == device->device_id)
> + return device;
> +
> + return NULL;
> +}
> +
> +/*
> + * Find and returns an interrupt translation table entry (ITTE) for a given
> + * Device ID/Event ID pair on an ITS.
> + * Must be called with the its_lock mutex held.
> + */
> +static struct its_itte *find_itte(struct vgic_its *its, u32 device_id,
> + u32 event_id)
> +{
> + struct its_device *device;
> + struct its_itte *itte;
> +
> + device = find_its_device(its, device_id);
> + if (device == NULL)
> + return NULL;
> +
> + list_for_each_entry(itte, &device->itt_head, itte_list)
> + if (itte->event_id == event_id)
> + return itte;
> +
> + return NULL;
> +}
> +
> +/* To be used as an iterator this macro misses the enclosing parentheses */
> +#define for_each_lpi_its(dev, itte, its) \
> + list_for_each_entry(dev, &(its)->device_list, dev_list) \
> + list_for_each_entry(itte, &(dev)->itt_head, itte_list)
> +
> #define CBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 12))
> #define PENDBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 16))
> #define PROPBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 12))
>
> #define GIC_LPI_OFFSET 8192
>
> +/*
> + * Finds and returns a collection in the ITS collection table.
> + * Must be called with the its_lock mutex held.
> + */
> +static struct its_collection *find_collection(struct vgic_its *its, int coll_id)
> +{
> + struct its_collection *collection;
> +
> + list_for_each_entry(collection, &its->collection_list, coll_list) {
> + if (coll_id == collection->collection_id)
> + return collection;
> + }
> +
> + return NULL;
> +}
> +
> #define LPI_PROP_ENABLE_BIT(p) ((p) & LPI_PROP_ENABLED)
> #define LPI_PROP_PRIORITY(p) ((p) & 0xfc)
>
> @@ -141,6 +260,48 @@ static int vgic_copy_lpi_list(struct kvm *kvm, u32 **intid_ptr)
> }
>
> /*
> + * Promotes the ITS view of affinity of an ITTE (which redistributor this LPI
> + * is targeting) to the VGIC's view, which deals with target VCPUs.
> + * Needs to be called whenever either the collection for a LPIs has
> + * changed or the collection itself got retargeted.
> + */
> +static void update_affinity_itte(struct kvm *kvm, struct its_itte *itte)
> +{
> + struct kvm_vcpu *vcpu;
> +
> + vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr);
What happens if the collection hasn't been mapped yet? It is probably
worth checking before blindly assigning a NULL pointer, which would
corrupt the state set by another ITS.
> +
> + spin_lock(&itte->irq->irq_lock);
> + itte->irq->target_vcpu = vcpu;
> + spin_unlock(&itte->irq->irq_lock);
> +}
> +
> +/*
> + * Updates the target VCPU for every LPI targeting this collection.
> + * Must be called with the its_lock mutex held.
> + */
> +static void update_affinity_collection(struct kvm *kvm, struct vgic_its *its,
> + struct its_collection *coll)
> +{
> + struct its_device *device;
> + struct its_itte *itte;
> +
> + for_each_lpi_its(device, itte, its) {
> + if (!itte->collection || coll != itte->collection)
> + continue;
> +
> + update_affinity_itte(kvm, itte);
> + }
> +}
> +
> +static u32 max_lpis_propbaser(u64 propbaser)
> +{
> + int nr_idbits = (propbaser & 0x1f) + 1;
> +
> + return 1U << min(nr_idbits, INTERRUPT_ID_BITS_ITS);
> +}
> +
> +/*
> * Scan the whole LPI pending table and sync the pending bit in there
> * with our own data structures. This relies on the LPI being
> * mapped before.
> @@ -275,10 +436,446 @@ static void its_free_itte(struct kvm *kvm, struct its_itte *itte)
> kfree(itte);
> }
>
> +static u64 its_cmd_mask_field(u64 *its_cmd, int word, int shift, int size)
> +{
> + return (le64_to_cpu(its_cmd[word]) >> shift) & (BIT_ULL(size) - 1);
> +}
> +
> +#define its_cmd_get_command(cmd) its_cmd_mask_field(cmd, 0, 0, 8)
> +#define its_cmd_get_deviceid(cmd) its_cmd_mask_field(cmd, 0, 32, 32)
> +#define its_cmd_get_id(cmd) its_cmd_mask_field(cmd, 1, 0, 32)
> +#define its_cmd_get_physical_id(cmd) its_cmd_mask_field(cmd, 1, 32, 32)
> +#define its_cmd_get_collection(cmd) its_cmd_mask_field(cmd, 2, 0, 16)
> +#define its_cmd_get_target_addr(cmd) its_cmd_mask_field(cmd, 2, 16, 32)
> +#define its_cmd_get_validbit(cmd) its_cmd_mask_field(cmd, 2, 63, 1)
> +
> +/*
> + * The DISCARD command frees an Interrupt Translation Table Entry (ITTE).
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_discard(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + u32 device_id;
> + u32 event_id;
> + struct its_itte *itte;
> +
> + device_id = its_cmd_get_deviceid(its_cmd);
> + event_id = its_cmd_get_id(its_cmd);
> +
> + itte = find_itte(its, device_id, event_id);
> + if (itte && itte->collection) {
> + /*
> + * Though the spec talks about removing the pending state, we
> + * don't bother here since we clear the ITTE anyway and the
> + * pending state is a property of the ITTE struct.
> + */
> + its_free_itte(kvm, itte);
> + return 0;
> + }
> +
> + return E_ITS_DISCARD_UNMAPPED_INTERRUPT;
> +}
> +
> +/*
> + * The MOVI command moves an ITTE to a different collection.
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + u32 device_id = its_cmd_get_deviceid(its_cmd);
> + u32 event_id = its_cmd_get_id(its_cmd);
> + u32 coll_id = its_cmd_get_collection(its_cmd);
> + struct kvm_vcpu *vcpu;
> + struct its_itte *itte;
> + struct its_collection *collection;
> +
> + itte = find_itte(its, device_id, event_id);
> + if (!itte)
> + return E_ITS_MOVI_UNMAPPED_INTERRUPT;
> +
> + if (!its_is_collection_mapped(itte->collection))
> + return E_ITS_MOVI_UNMAPPED_COLLECTION;
> +
> + collection = find_collection(its, coll_id);
> + if (!its_is_collection_mapped(collection))
> + return E_ITS_MOVI_UNMAPPED_COLLECTION;
> +
> + itte->collection = collection;
> + vcpu = kvm_get_vcpu(kvm, collection->target_addr);
> +
> + spin_lock(&itte->irq->irq_lock);
> + itte->irq->target_vcpu = vcpu;
> + spin_unlock(&itte->irq->irq_lock);
> +
> + return 0;
> +}
> +
> +static void vgic_its_init_collection(struct vgic_its *its,
> + struct its_collection *collection,
> + u32 coll_id)
> +{
> + collection->collection_id = coll_id;
> + collection->target_addr = COLLECTION_NOT_MAPPED;
> +
> + list_add_tail(&collection->coll_list, &its->collection_list);
> +}
> +
> +/*
> + * The MAPTI and MAPI commands map LPIs to ITTEs.
> + * Must be called with its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd, u8 subcmd)
> +{
> + u32 device_id = its_cmd_get_deviceid(its_cmd);
> + u32 event_id = its_cmd_get_id(its_cmd);
> + u32 coll_id = its_cmd_get_collection(its_cmd);
> + struct its_itte *itte;
> + struct its_device *device;
> + struct its_collection *collection, *new_coll = NULL;
> + int lpi_nr;
> +
> + device = find_its_device(its, device_id);
> + if (!device)
> + return E_ITS_MAPTI_UNMAPPED_DEVICE;
> +
> + collection = find_collection(its, coll_id);
Don't you need to check the range of the collection ID, and whether it
would fit in the collection table?
> + if (!collection) {
> + new_coll = kzalloc(sizeof(struct its_collection), GFP_KERNEL);
> + if (!new_coll)
> + return -ENOMEM;
> + }
> +
> + if (subcmd == GITS_CMD_MAPTI)
> + lpi_nr = its_cmd_get_physical_id(its_cmd);
> + else
> + lpi_nr = event_id;
> + if (lpi_nr < GIC_LPI_OFFSET ||
> + lpi_nr >= max_lpis_propbaser(kvm->arch.vgic.propbaser)) {
> + kfree(new_coll);
> + return E_ITS_MAPTI_PHYSICALID_OOR;
> + }
> +
> + itte = find_itte(its, device_id, event_id);
> + if (!itte) {
> + itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);
> + if (!itte) {
> + kfree(new_coll);
> + return -ENOMEM;
> + }
> +
> + itte->event_id = event_id;
> + list_add_tail(&itte->itte_list, &device->itt_head);
> + }
> +
> + if (!collection) {
> + collection = new_coll;
> + vgic_its_init_collection(its, collection, coll_id);
> + }
> +
> + itte->collection = collection;
> + itte->lpi = lpi_nr;
> + itte->irq = vgic_add_lpi(kvm, lpi_nr);
> + update_affinity_itte(kvm, itte);
> +
> + /*
> + * We "cache" the configuration table entries in out struct vgic_irq's.
> + * However we only have those structs for mapped IRQs, so we read in
> + * the respective config data from memory here upon mapping the LPI.
> + */
> + update_lpi_config(kvm, itte->irq, NULL);
> +
> + return 0;
> +}
> +
> +/* Requires the its_lock to be held. */
> +static void vgic_its_unmap_device(struct kvm *kvm, struct its_device *device)
> +{
> + struct its_itte *itte, *temp;
> +
> + /*
> + * The spec says that unmapping a device with still valid
> + * ITTEs associated is UNPREDICTABLE. We remove all ITTEs,
> + * since we cannot leave the memory unreferenced.
> + */
> + list_for_each_entry_safe(itte, temp, &device->itt_head, itte_list)
> + its_free_itte(kvm, itte);
> +
> + list_del(&device->dev_list);
> + kfree(device);
> +}
> +
> +/*
> + * MAPD maps or unmaps a device ID to Interrupt Translation Tables (ITTs).
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + bool valid = its_cmd_get_validbit(its_cmd);
> + u32 device_id = its_cmd_get_deviceid(its_cmd);
> + struct its_device *device;
> +
> + device = find_its_device(its, device_id);
> + if (device)
> + vgic_its_unmap_device(kvm, device);
Maybe add a comment as to *why* it is legal to do so.
> +
> + /*
> + * The spec does not say whether unmapping a not-mapped device
> + * is an error, so we are done in any case.
> + */
> + if (!valid)
> + return 0;
> +
> + device = kzalloc(sizeof(struct its_device), GFP_KERNEL);
> + if (!device)
> + return -ENOMEM;
> +
> + device->device_id = device_id;
> + INIT_LIST_HEAD(&device->itt_head);
> +
> + list_add_tail(&device->dev_list, &its->device_list);
> +
> + return 0;
> +}
> +
> +/*
> + * The MAPC command maps collection IDs to redistributors.
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_mapc(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + u16 coll_id;
> + u32 target_addr;
> + struct its_collection *collection;
> + bool valid;
> +
> + valid = its_cmd_get_validbit(its_cmd);
> + coll_id = its_cmd_get_collection(its_cmd);
> + target_addr = its_cmd_get_target_addr(its_cmd);
> +
> + if (target_addr >= atomic_read(&kvm->online_vcpus))
> + return E_ITS_MAPC_PROCNUM_OOR;
> +
> + collection = find_collection(its, coll_id);
> +
> + if (!valid) {
> + struct its_device *device;
> + struct its_itte *itte;
> + /*
> + * Clearing the mapping for that collection ID removes the
> + * entry from the list. If there wasn't any before, we can
> + * go home early.
> + */
> + if (!collection)
> + return 0;
> +
> + for_each_lpi_its(device, itte, its)
> + if (itte->collection &&
> + itte->collection->collection_id == coll_id)
> + itte->collection = NULL;
> +
> + list_del(&collection->coll_list);
> + kfree(collection);
> + } else {
> + if (!collection) {
> + collection = kzalloc(sizeof(struct its_collection),
> + GFP_KERNEL);
> + if (!collection)
> + return -ENOMEM;
> +
> + vgic_its_init_collection(its, collection, coll_id);
> + collection->target_addr = target_addr;
> + } else {
> + collection->target_addr = target_addr;
> + update_affinity_collection(kvm, its, collection);
> + }
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * The CLEAR command removes the pending state for a particular LPI.
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_clear(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + u32 device_id;
> + u32 event_id;
> + struct its_itte *itte;
> +
> + device_id = its_cmd_get_deviceid(its_cmd);
> + event_id = its_cmd_get_id(its_cmd);
> +
> + itte = find_itte(its, device_id, event_id);
> + if (!itte)
> + return E_ITS_CLEAR_UNMAPPED_INTERRUPT;
> +
> + itte->irq->pending = false;
> +
> + return 0;
> +}
> +
> +/*
> + * The INV command syncs the configuration bits from the memory table.
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_inv(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + u32 device_id;
> + u32 event_id;
> + struct its_itte *itte;
> +
> + device_id = its_cmd_get_deviceid(its_cmd);
> + event_id = its_cmd_get_id(its_cmd);
> +
> + itte = find_itte(its, device_id, event_id);
> + if (!itte)
> + return E_ITS_INV_UNMAPPED_INTERRUPT;
> +
> + return update_lpi_config(kvm, itte->irq, NULL);
> +}
> +
> +/*
> + * The INVALL command requests flushing of all IRQ data in this collection.
> + * Find the VCPU mapped to that collection, then iterate over the VM's list
> + * of mapped LPIs and update the configuration for each IRQ which targets
> + * the specified vcpu. The configuration will be read from the in-memory
> + * configuration table.
> + * Must be called with the its_lock mutex held.
> + */
> +static int vgic_its_cmd_handle_invall(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + u32 coll_id = its_cmd_get_collection(its_cmd);
> + struct its_collection *collection;
> + struct kvm_vcpu *vcpu;
> + struct vgic_irq *irq;
> + u32 *intids;
> + int irq_count, i;
> +
> + collection = find_collection(its, coll_id);
> + if (!its_is_collection_mapped(collection))
> + return E_ITS_INVALL_UNMAPPED_COLLECTION;
> +
> + vcpu = kvm_get_vcpu(kvm, collection->target_addr);
> +
> + irq_count = vgic_copy_lpi_list(kvm, &intids);
> + if (irq_count < 0)
> + return irq_count;
> +
> + for (i = 0; i < irq_count; i++) {
> + irq = vgic_get_irq(kvm, NULL, intids[i]);
> + if (!irq)
> + continue;
> + update_lpi_config(kvm, irq, vcpu);
> + vgic_put_irq(kvm, irq);
> + }
> +
> + kfree(intids);
> +
> + return 0;
> +}
> +
> +/*
> + * The MOVALL command moves the pending state of all IRQs targeting one
> + * redistributor to another. We don't hold the pending state in the VCPUs,
> + * but in the IRQs instead, so there is really not much to do for us here.
> + * However the spec says that no IRQ must target the old redistributor
> + * afterwards, so we make sure that no LPI is using the associated target_vcpu.
> + * This command affects all LPIs in the system.
Or rather all LPIs targetting the "old" redistributor.
> + */
> +static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
> + u64 *its_cmd)
> +{
> + struct vgic_dist *dist = &kvm->arch.vgic;
> + u32 target1_addr = its_cmd_get_target_addr(its_cmd);
> + u32 target2_addr = its_cmd_mask_field(its_cmd, 3, 16, 32);
> + struct kvm_vcpu *vcpu1, *vcpu2;
> + struct vgic_irq *irq;
> +
> + if (target1_addr >= atomic_read(&kvm->online_vcpus) ||
> + target2_addr >= atomic_read(&kvm->online_vcpus))
> + return E_ITS_MOVALL_PROCNUM_OOR;
> +
> + if (target1_addr == target2_addr)
> + return 0;
> +
> + vcpu1 = kvm_get_vcpu(kvm, target1_addr);
> + vcpu2 = kvm_get_vcpu(kvm, target2_addr);
> +
> + spin_lock(&dist->lpi_list_lock);
> +
> + list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
> + spin_lock(&irq->irq_lock);
> +
> + if (irq->target_vcpu == vcpu1)
> + irq->target_vcpu = vcpu2;
> +
> + spin_unlock(&irq->irq_lock);
> + }
> +
> + spin_unlock(&dist->lpi_list_lock);
> +
> + return 0;
> +}
> +
> +/*
> + * This function is called with the its_cmd lock held, but the ITS data
> + * structure lock dropped.
> + */
> static int vgic_its_handle_command(struct kvm *kvm, struct vgic_its *its,
> u64 *its_cmd)
> {
> - return -ENODEV;
> + u8 cmd = its_cmd_get_command(its_cmd);
> + int ret = -ENODEV;
> +
> + mutex_lock(&its->its_lock);
> + switch (cmd) {
> + case GITS_CMD_MAPD:
> + ret = vgic_its_cmd_handle_mapd(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_MAPC:
> + ret = vgic_its_cmd_handle_mapc(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_MAPI:
> + ret = vgic_its_cmd_handle_mapi(kvm, its, its_cmd, cmd);
> + break;
> + case GITS_CMD_MAPTI:
> + ret = vgic_its_cmd_handle_mapi(kvm, its, its_cmd, cmd);
> + break;
> + case GITS_CMD_MOVI:
> + ret = vgic_its_cmd_handle_movi(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_DISCARD:
> + ret = vgic_its_cmd_handle_discard(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_CLEAR:
> + ret = vgic_its_cmd_handle_clear(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_MOVALL:
> + ret = vgic_its_cmd_handle_movall(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_INV:
> + ret = vgic_its_cmd_handle_inv(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_INVALL:
> + ret = vgic_its_cmd_handle_invall(kvm, its, its_cmd);
> + break;
> + case GITS_CMD_SYNC:
> + /* we ignore this command: we are in sync all of the time */
> + ret = 0;
> + break;
> + }
> + mutex_unlock(&its->its_lock);
> +
> + return ret;
> }
>
> static u64 vgic_sanitise_its_baser(u64 reg)
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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